The Home Machinist!

I finally have something for the build forum! I don't have welders or a lot of fancy machine tools, but I do have a fairly large capacity foundry. So, I have been working on patterns for a Plymouth like switcher, and managed to collect enough round tuits for a casting session for myself yesterday. I'm very happy with the results, I had very close to 100% sucess rate, the only minor flaw was a few holes in the hood casting, but it's nothing that a little bondo won't fix. The second pic is a mockup of the available pieces, I have a few more patterns to make, the cowl sides and the cab. If all goes well I should have it running by summer.

I like it............

John B

My experience with a Lil' Gasser was that of crash and break. Some parts too light, and broke in derailments.

But if you have the capability, why not.

I am jealous in that I wanted my foundry set up in January, and here it s Nearly March, and I am not moved forward much. Typical.

Are the frames cast aluminum?

Yes, haven't weighed them, probably close to 10 lbs each. They are about 3/4" thick. Here's a few more pics. The mold is about as big as I care to handle.

Aluminum, interesting. Have others been successful with aluminum for frames? Seems like if aluminum was the perfect thing to use, all frames would be aluminum considering it is quite a bit easier to machine than steel. I'm sure aluminum would be great for body and cab parts. I would be apprehensive about using it for frames. Perhaps this is done all the time, I have just not seen it before.

David

Builder01 wrote:Aluminum, interesting. Have others been successful with aluminum for frames? Seems like if aluminum was the perfect thing to use, all frames would be aluminum considering it is quite a bit easier to machine than steel. I'm sure aluminum would be great for body and cab parts. I would be apprehensive about using it for frames. Perhaps this is done all the time, I have just not seen it before.

David

An opinion (mine) only.
Aluminum*, especially cast aluminum, is not known for its excessive tensile strength (poor ductility). It, like cast gray iron, fractures easily when bending forces are applied. For that reason, I wouldn't recommend an aluminum frame, assuming it would be subjected to unacceptable forces such as might be experienced in a derailment, or other catastrophe.

That being said, I am not aware of many who hope to see the weight of an engine diminished, especially on very small engines, where tractive force is always an issue. Any benefits from the use of aluminum will come at the cost of performance capabilities.

However, what ever floats one's boat is good enough for me (so long as chosen methods don't endanger others). I may not emulate such practice, but it is not for me to say that others should not, as none of us have the least idea what the other guy is capable of dealing with. For all we know, none of these considerations are an issue, and an aluminum frame is in this individual's best interest. It will be interesting to hear how things shake out when it is put in service.

Harold

*There are grades of aluminum that rival the tensile strength of steel. They are not, however, casting grades of aluminum.

The allen models Chloe was designed for a cast aluminum frame to be used. I know there have been several that were built using it, which have run successfully. Upgrading it to a solid steel frame is one of the common upgrades done to them. The steel frame is stronger and it does add weight, and a small locomotive like that will need it.

Also, the small one-piece cast frame of the Chloe is often a machining problem because it will warp as you machine it. I don't think he'll have that problem with these, as they are made in two sides not as an entire frame.

His frames seem pretty darn thick and well made. Add a pedestal binder across the bottom and a flat sheet of steel across the top for the deck, and I doubt that he'll ever have any problems with breaking them.

There is also the fact that all aluminum is not the same.

There are many exotics that are used in aviation that has strength approaching steel and others with weight approaching cast iron. Depends on the Alloy.

This aluminum was sourced from auto wheels, should be pretty rugged for the application. Yes, Pipescs, I'm putting steel across the bottom, the deck at the moment will probably be plywood. I don't have the budget for fancy stuff like steel and waterjetting, etc. If this frame breaks in a derailment I was going waaaaay to fast, I have absolutely no worries on that score. Thanks for the observations, everyone, this is my first loco and I'm sure I'll learn a lot from it.

What are you looking at for a powertrain?

A friend gave me the guts from a power wheelchair, I've got two motors with attached right angle transmissions, and all the associated controls and wiring. I'm going to use one motor per loco, chain drive to one axle and chain from the driven axle to the other axle. I had a thought of building two switchers, link them with a drawbar, and run both so I don't have to modify the electronics. I think in effect this would give me more or less the equivalent of a large loco with both trucks driven. Oh, I also plan to have the battery on the loco for added weight, I think I will have enough room under the skin if I can find the right battery.